The present invention relates to a thermoplastic resin laminate produced by firmly bonding two layers composed respectively of different types of thermoplastic resins which are not bonded each other.
As a conventional laminating method of bonding two layers composed respectively of a thermoplastic resin A and a thermoplastic resin B, which are not. bonded each other, for example, a method of chemically modifying the surface and a method of physically modifying the surface by means of sputtering, corona discharge, plasma, excimer laser, etc. are known. These methods had a problem that an interlaminar bonding force is small although a special processing device is required. Furthermore, in order to obtain a resin laminate, a successive melt molding is required and therefore the number of steps at the time of molding increases, which results in poor processing productivity.
Even if a simultaneous co-extrusion method is used, it was limited to a co-extrusion method using a thermoplastic resin C which is bonded to both thermoplastic resin A and thermoplastic resin B.
The present invention provides a thermoplastic resin laminate comprising at least three thermoplastic resin layers, wherein an intermediate layer interposed between a first layer comprising a thermoplastic resin A1 and a second layer comprising a thermoplastic resin B1, which are not bonded each other, comprises a thermoplastic resin composition which comprises as a main component a thermoplastic resin A2 having a bonding property to the thermoplastic resin A1 and a thermoplastic resin B2 having a bonding property to the thermoplastic resin B1 and forms a dispersion structure, wherein the thermoplastic resin A2 forms a continuous phase and the thermoplastic resin B2 forms a dispersed phase in the intermediate layer at the vicinity of the interface between the intermediate layer and the first layer, and wherein the thermoplastic resin B2 forms the continuous phase and the thermoplastic resin A2 forms the dispersed phase in the intermediate layer at the vicinity of the interface between the intermediate layer and the second layer.
According to the present invention, a firm bonding strength can be accomplished between the first layer of the thermoplastic resin A1 and the second layer of the thermoplastic resin B1.